58 



NORTH AMERICAN DIPTKRA. 



information to bear upon his views, though he by no 

 means claimed finality for them. His exceptions, how- 

 ever, are so many and oftentimes so pertinent that I am 

 by no means convinced about many things. Wherein 

 all writers concur may safely be accepted by the stu- 

 dent ex autlwritate, but I would advise the inexpert 

 student to make no use of most of the terms that have 

 been proposed; nor fret himself about the value of any of 

 them. The divisions Orthorrhapha and Cyclorrhapha 

 may perhaps safely be accepted, since all, or nearly all, 

 are agreed thereon, though by no means agreed as to 

 their rank and limits. At one time, indeed, they were 

 almost universally accepted as the two chief suborders, 

 but within recent years there has been a tendency to sub- 

 ordinate them to the older groupings of Latreille and 

 Macquart, perhaps in part due to the influence of Osten 

 Sacken's authority. Osten Sacken endeavored to show 

 that the characters recognized as distinctive of the Ne- 

 mocera and Brachycera are of more fundamental import- 

 ance than those distinguishing the Orthorrhapha and 

 Cyclorrhapha. With this view I do not agree. I must 

 Still accept Brauer's chief divisions, as, upon the whole, 

 the most natural grouping of the order. 



Speiser believes that the Pupipara are only highly 

 specialized muscids, and it is even doubtful yet whether 

 some of them may not be oviparous in habit; we know 

 of one species, at least, wingless and parasitic upon birds 

 which stands on the border line. Wesche has recently 

 asserted that the mouth-parts of the Pupipara are thor- 

 oughly muscid in structure. The vestigial eyes, small 

 and partly aborted antennae, bristly head, leathery abdo- 

 men and short stout legs are also characteristic of certain 

 wingless, parasitic Phoridas, ami certainly no one will 

 attempt to trace any immediate relationship with these 

 tlies. I believe there is a much closer relationship be- 



